For a conventional control device with a dial wheel mechanism, external forces are used to rotate the dial wheel to a desired gear position, and information of the gear position is input to a controller of the control device, thereby realizing control of an external device. This kind of dial wheel mechanism generally uses a spring plunger structure to engage with or separate from the dial wheel to change gear position. However, specific mounting structures and components are needed to install the spring plunger structure, which makes the overall volume of the dial wheel mechanism relatively large, and the structure and assembling process of the dial wheel mechanism complicated.